When the two children balance on a seesaw on Earth, they do so based on their weights and the distances from the pivot point of the seesaw. The seesaw is balanced when the torque (rotational force) created by each child is equal. Torque is calculated as \( \text{Torque} = \text{Force} \times \text{Distance} \), where the Force is the weight of the child (mass times gravitational acceleration).
On the Moon, the gravitational acceleration is about 1/6th that of Earth's. Therefore, while the weight of the children will be less on the Moon, their mass remains the same. When the children move to the Moon, they will experience a decrease in weight, but the ratio of their masses and the distances from the pivot will remain unchanged.
As a result, if they were perfectly balanced on Earth, they will also be perfectly balanced on the Moon. The seesaw will still balance as long as their positioning relative to the pivot point remains the same. The key factor in balance is the proportionality of the torque about the pivot, which will not change due to the different gravitational forces.